The present invention relates to a system and method for regulating the operation of an irrigation system. More particularly, the invention pertains to a system and method for regulating the operation of an irrigation system which is responsive to user programmed information.
Automatic irrigation systems such as those employed for landscape and agricultural watering are well known in the art. Typical irrigation systems use a means of controlling watering cycles via an automatic controller. The need to control watering cycles due to seasonally changing environmental conditions is important for saving water, saving costs, optimizing growing conditions, and preventing unsafe conditions.
Typically, a user will enter instructions into a microprocessor based controller that will cause the irrigation system to start irrigation at a certain time, on certain days, for a certain duration, according to the user's instructions. Irrigation may be based on “zones” in which a group of sprinkler heads discharge in unison, or sequentially, or a combination of both.
Typically, a user who programs the microprocessor in the summer month of July to deliver an irrigation event of a certain duration on certain days from a particular irrigation system, would, if reminded to attend to the issue, reduce that duration over the fall, winter, and spring months to take account of changing seasonal environmental conditions that can be expected to prevail in the vicinity of the irrigation system, and the user might reduce the duration accordingly each month, or shorter period, before increasing it again. Frequently, however, many users tend to forget to downwardly adjust the irrigation duration after the hot summer months to account for the reduced evapo-transpiration rates over the following months. At best, a user may remember to adjust irrigation for some months or a shorter period, but not others. As a result, the irrigation system may continue to discharge water in irrigation during the fall and winter at a rate that was selected to be suitable during the summer, or some other time. This can be very wasteful, not to mention destructive in the case of certain crops, grasses, flowers, and shrubs that react adversely to over or under watering.
Consequently, solutions have been developed for taking into account actual prevailing environmental conditions, and for automatically adjusting irrigation duration to take account of changed conditions in real time. These solutions typically employ one or more sensors that monitor changes in environmental conditions in real time. (As used herein, the term “real time data” refers to information that is acquired for immediate use, and is distinguished from “historical data” which refers to data collected on one date in one year for use on a similar date in a later year. Average historic data is data from a plurality of previous years that has been averaged to provide one mean value.) A sensor may be located near an associated controller, and may be linked to the controller either by wireless communication or by physical connection. Such a sensor may measure actual precipitation, actual temperatures, actual wind speed, soil moisture, humidity, and other environmental factors, all in real time. Based on these measurements which are transmitted back to the controller, the controller uses preprogrammed logical algorithms to decide how to adjust a preprogrammed irrigation schedule to account for changed environmental conditions. For example, if high temperatures and dry conditions are recorded, irrigation duration may be increased. If wet or cold conditions are noted, irrigation may be reduced or suspended altogether.
However, such weather sensor based systems may have drawbacks and disadvantages. Typically, weather sensors are mounted where they are exposed to the elements and once mounted may malfunction, or may be difficult to maintain in operation. Thus, while a failed sensor is awaiting repair, the controller may be obliged to discharge an amount of irrigation water that is not adjusted for prevailing weather conditions, and that may therefore be wasteful and/or destructive.
Accordingly, there is a need in the art for a weather based irrigation controller that may be sold and used universally, that is easy to use, that is inexpensive to manufacture, that is easy to install, initialize, maintain, and operate, but that also takes account of the fact that weather sensors may fail after installation in that it does not surrender all ability to adjust for seasonal weather variation in the event of such failure. The present invention addresses these and other needs.